I have a 1KW system 9 months old and when I climbed on roof to clean panels I found 5 panels had a creamy/yellow color substrate whilst the last one was white.This prompted me to check the serial numbers and the 5 colored ones had numbers within 100 of each other but the white one had a serial number some 9 million later.I am no rocket scientist but something here does'nt gel I feel that the 5 colored panels may be second hand.although the frames appear to be new.Has anyone else any ideas on this. For obvious reasons I do not wish to name the brand of panel or the supplier.I did query the suppliers who assured me they were new panels but were at a loss to explain why different color and serial numbers.

It could possibly be a quality control problem in manufacturing, maybe you got a bad batch, or one with a slightly different material (manufacturers do change suppliers over time)

Were the panels always like this or has the color change happened over time?Has there been any noticeable degradation in performance? If not I probably would just keep an eye on them and make sure it doesnt get worse. Unless you particularly care about the colour...

I'm not sure if this is with all manufacturers, but my panels show the date of manufacture as part of the serial number - eg: JW0395201004240213 - the 20100424 is the date. I think the 0395 might be a batch number, and the 0213 the actual panel number.

Hi,I have also experinced yellowing of my solar panels within a short time after installation. It is my opinion that whist the yellowing may not effect performance now how can you be sure of that in the future. The 25 year performance warranty is mandatory for all panels. I approached the supplier/importer of my panels and argued sucessfully that it was a manufacturing defect and ALL (30) panels were replaced under warranty. PM me if require further details.

Wayne Xantrax 5.0GT with 30 x 190w panels in three arrays northern roofXantrax 5.0GT with 30 x 190w panels in three arrays western roofConergy 400 ltr SHWS northern roofInsist on products built up to a standard not down to a price. Caveat Emptor.

RJS wrote:This prompted me to check the serial numbers and the 5 colored ones had numbers within 100 of each other but the white one had a serial number some 9 million later.I am no rocket scientist but something here does'nt gel I feel that the 5 colored panels may be second hand.although the frames appear to be new.Has anyone else any ideas on this.

you presumably signed some paperwork 9 months ago related to RECs on your system which should have had the seiral numbers for the panels in question.

suggest you check what paperwork you signed, and if you got the RECs for them.

I vaguely recall reading that yellowing of the panel glass is due to iron content of the glass. Cheaper panels may have higher iron content and prone to changing colour. No idea how much it affects panel output though. It wouldn't be cheap to send one away to get tested, but certainly follow up the manufacturer's or installer's warranty. If the installer claims there is nothing to worry about, I'd be asking them to prove this in writing!